Unit 3 Test Study Guide (Genetics)
NEED TO KNOW vocabulary:
Asexual reproduction
Sexual reproduction
Heredity
Genes
Chromosomes
Alleles
Genotype
Phenotype
Dominant trait
Recessive trait
Homozygous / Purebred
Heterozygous / Hybrid
Genetic Engineering
Selective breeding
Inbreeding
Punnett Square
Gamete
Reproduction using ONE parent
Examples of organisms that reproduce this way: bacteria, yeast (mostly
unicellular, some multicellular organisms)
3 types: Binary fission, regeneration, budding
Reproduction using TWO parents
Examples of organisms that reproduce this way: most multicellular organisms
(humans, pigs, fish, etc.)
Passing of genes from parents to offspring
A unit of heredity that is located at a certain point on a chromosome. Each gene
codes for a particular trait.
Structures inside the nucleus of a cell that stores genetic information. Genes are
located here.
Various forms of the same gene. We represent these with singular letters.
Examples: B, b
The name for the genes an organism has. We represent the genotype with a pair
of alleles (two letters).
Examples: BB, Bb, bb
Characteristics of a trait that can be observed. This is what we actually see!
Examples: brown hair, blue eyes, dimples
A trait that will be expressed even if only one of the parents carries the trait.
We usually represent this with a capital letter!
Example: B
This trait will only be expressed if both of the parents carry and pass on the trait.
We represent this by a lowercase letter!
Example: b
A pair of alleles that are the SAME.
Examples: BB, bb
A pair of alleles that are DIFFERENT.
Example: Bb
The ability to alter the DNA of an organism in order to get the traits that are
desired.
Selecting two organisms with desired traits to serve as the parents of the next
generation.
Example: Horse breeders breed their two “fastest” horses in order to get more
horses that produce the same or faster results when racing.
When two organisms that have very similar or the same characteristics are
mated. Inbreeding increases the risk of recessive genetic disorders. Offspring
lack diversity.
A tool used to predict the traits of offspring in a genetic cross.
A sex cell (female = egg / male = sperm)
These cells have HALF the chromosomes of body cells. A human has 46
chromosomes in each body cell, and 23 in each of their sex cells.